The present invention relates to torque power tools.
Power tools are known in the art. One of such known tools is a pneumatic torque power tool. Other torque power tools are known to be driven electrically, hydraulically, manually or otherwise powered. Every torque power tool has an action force and an equal and opposite reaction force. In any of torque tools such as a pneumatic torque tool, a torque multiplier, an electric or hydraulic torque tool, the action force equals a reaction force in opposite direction. As tightening of fasteners is becoming a more precise art, accurate or at least even bolt loads is a requirement. However, this can not be accomplished with slugging wrenches or impact wrenches.
Torque power tools require a reaction arm to abut against an adjacent stationary object, so as to stop the tool from turning around a bolt and to turn a nut instead. In such torque power tools, the reaction arm is usually connected around an axis, and a mechanism is provided to hold the arm steadily relative to the tool housing during operation. This can be done with splines, hexagons, or other configurations.
The reason that torque power tools include a reaction arm is that the tools are unable to tighten and loosen fasteners, e.g., a nut, unless the tool housing is stopped from turning in the opposite direction. This means that the equal and opposite reaction force to the nut turning force has to be diverted for a torque power tool to function properly. Several examples of known torque power tools that include a reaction arm to abut against a stationary object are disclosed in U.S. Pat. No. 6,152,243, U.S. Pat. No. 6,253,642 and U.S. Pat. No. 6,715,381, commonly owned and incorporated by reference herein.
In known torque power tools with a reaction arm there is a significant risk that during intended use, operator's fingers or hand might be caught between the reaction arm and the abutment area when not paying attention. The stationary object or abutment area against which the necessary reaction arm abuts can be one of adjacent nuts, a housing of the application, a pipe of which the flange is part, etc.
The operator grasps the tool with an operating hand that also trigger torque tool operation. The hand other than the operating hand is free and might inadvertently move to the reaction arm, or proximate to the reaction arm at which the free hand can be caught as the reaction arm moves against a stationary object to find it abutment area while the operator triggers and activates the torque tool by the operating hand. This is one of the greatest dangers in bolting with torque power tools, and it happens frequently, since the reaction force applied by the tool is in most cases much larger than the LBS/FT torque as the portion of the reaction arm that abuts is often less than one-quarter of a foot away from the turning axis of the tool. Tools of this kind have and will amputate fingers. See page 5.
Injury to the free hand and its fingers known to be severe. Such accidents occur frequently, and require attention. At times not only the operator's work is stopped in response to injury, but an entire operation must stop. Anyone proximate an injury to a workforce member normally directs their attention to the injury, and the injured operator. So not only has the operator been injured and hurt, but the cost to the job or work task and loss in productivity is enormous. For that matter, such workforce accidents are normally subject to OSHA reporting requirements.